poj3264 线段树维护最大值最小值

来源：互联网发布：企业数据库管理系统编辑：程序博客网时间：2024/06/05 11:48

用线段树来维护区间的最大值最小值
建好线段树，就可以针对查询来查出最大值最小值

从而求出其差值

<span style="white-space:pre"></span>#include <set>#include <map>#include <queue>#include <stack>#include <deque>#include <math.h>#include <string>#include <vector>#include <stdio.h>#include <iostream>#include <string.h>#include <algorithm>#include <functional>#define mem(a) memset(a,0,sizeof(a));#define mem_1(a) memset(a,-1,sizeof(a));#define sf(a) scanf("%d",&a)#define sff(a,b) scanf("%d%d",&a,&b)#define sfff(a,b,c) scanf("%d%d%d",&a,&b,&c)#define lson l,mid,i<<1#define rson mid+1,r,i<<1|1const int INF = 0x7FFFFFFF;const int MAXN = 50100;const double PI = acos(-1.0);const double esp = 1e-10;using namespace std;struct node{int l,r,Max,Min;}Tree[MAXN<<2];int xx;int MAX,MIN;void build_tree(int l,int r,int i){Tree[i].l = l;Tree[i].r = r;if(l == r){sf(xx);Tree[i].Max = Tree[i].Min = xx;return ;}int mid = (l+r)>>1;build_tree(lson);build_tree(rson);Tree[i].Max = max(Tree[i<<1].Max,Tree[i<<1|1].Max);Tree[i].Min = min(Tree[i<<1].Min,Tree[i<<1|1].Min);}void Query(int l,int r,int i){if(Tree[i].l == l && Tree[i].r ==r){MAX = max(MAX,Tree[i].Max);MIN = min(MIN,Tree[i].Min);return ;}int mid = (Tree[i].l + Tree[i].r) >>1;if(r <= mid) Query(l,r,i<<1);else if(mid < l) Query(l,r,i<<1|1);else{Query(lson);Query(rson);}}int main(){int n,m,x,y;sff(n,m);build_tree(1,n,1);while(m--){sff(x,y);MAX = -1;MIN = INF;Query(x,y,1);printf("%d\n",MAX - MIN);}}

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